A rotary electric machine mounted on a vehicle or the like and used as an electric motor or a generator includes a stator, a rotor, a pair of end plates, and a casing. As an electric motor, there is a motor using a rotor in which a permanent magnet is embedded. Each of a pair of the end plates is disposed at a front end portion and a rear end portion in an axial direction of a rotor formed by laminating electromagnetic steel plates and having a permanent magnet embedded therein, and supports the permanent magnet. Leakage of an adhesive that bonds the permanent magnet and the electromagnetic steel plate may be prevented by the end plates. Since electric motors used in electric vehicles and hybrid vehicles are required to have high power, in general, permanent magnet electric motors using rare earth sintered magnets that retain strong energy are used. An embedded magnet type electric motor can satisfy the requirements of low speed, large torque, and wide range of rotational speed range.
Generally, a rotating shaft and a rotor core are assembled to a rotor by press-fitting or shrink-fitting. In the press-fitting method, by performing knurling on an outer peripheral surface of a rotating shaft, press-fitting load can be reduced. However, in the method by press-fitting or shrink-fitting, fitting is performed at a predetermined interference such that compressive stress is applied to a rotor core, and there is a problem that electrical characteristics may be deteriorated. To solve this problem, a gap is provided between a rotor core and a rotating shaft subjected to knurling, and when an end plate is formed by casting, a part of a molten metal at the time of casting is filled in the gap. Thereby the rotating shaft and the rotor core are fixed (refer to, for example, PTL 1).